1. Field of the Invention
The present invention is generally related to a steering sensor system for a marine vessel and, more particularly, to an arrangement of guides and pins which allow a rotary sensor to monitor the movement of a steering actuator even though the paths of the steering actuator and the movable portion of the sensor are different from each other.
2. Description of the Prior Art
Many different types of power steering systems are well known to those skilled in the art of marine propulsion systems and marine vessel steering systems. Furthermore, many different types of position sensors, including Hall effect sensors, are well known to those skilled in the art of position sensing.
U.S. Pat. No. 5,389,016, which issued to Nestvall on Feb. 14, 1995, describes a steering system for planing watercraft. The arrangement in a steering and propulsion system for a planing type motorboat is described. The boat is provided with a means for adjusting the trim position. Steering characteristics of the boat are improved by providing the steering mechanism with a sensor for detecting rudder displacement. The sensor is connected to the trim position adjustment means via a microprocessor for recording the degree of steering displacement and is adapted to trim down the bow of the boat in the water when a certain steering displacement is exceeded.
U.S. Pat. No. 4,744,322, which issued to Nakase on May 17, 1988, describes a remote steering system for a marine propulsion craft. Several embodiments of the improved mechanisms for controlling an outboard drive of a marine watercraft are disclosed. In each embodiment, there is provided a hand held control unit that permits remote steering and engine control of the watercraft. In some embodiments, the hand held control includes a rotatable control element for effecting steering and a reciprocating control element for killing the engine. In some embodiments, the controls for the engine and steering are designed to be operated by different fingers of the user and in other embodiments, they are designed so as to be operated by the same finger of the operator. In addition, there is included an improved sensor for sensing the steered position of the outboard drive.
U.S. Pat. No. 5,694,039, which issued to Alfors on Dec. 2, 1997, describes an angular position sensor having multiple magnet circuits. The rotational position sensor, or angular position sensor, has two pole pieces. Each of the pole pieces has a first end portion and a second end portion. The two end portions are arranged in overlapping parallel association to provide a gap therebetween. Two magnetically sensitive components are disposed in the gap between the second end portions of the two pole pieces. The two magnetically sensitive components are used to provide redundancy in the event that one of the magnetically sensitive components experiences a failure.
U.S. Pat. No. 5,627,465, which issued to Alfors et al on May 6, 1997, describes a rotational position sensor with mechanical adjustment of offset and gain signals. The sensor is provided with a rotatable magnetic structure that comprises a primary magnet and a secondary magnet. The primary and secondary magnets are adjusted in position relative to each other in order to achieve an adjustability of the gain and offset characteristics of an output signal from a magnetically sensitive component disposed within the magnetic field of the magnetic structure. The primary and secondary magnets are rigidly maintained in position relative to each other and disposed for rotation about an axis of rotation. Each magnet has a magnetic axis extending through its first and second magnet poles. The two magnetic axes rotate within parallel planes that are each perpendicular to the axis of rotation of the magnetic structure.
U.S. Pat. No. 5,512,820, which issued to Alfors on Apr. 30, 1996, describes a rotational position sensor with a two-part rotatable member to resist jamming. A rotational position sensor is provided with a rotatable member that comprises first and second portions. The first portion is generally cylindrical and has an opening that is shaped to receive the second portion therein with a resilient spring disposed in the annular gap between the first and second portions when this assembly is accomplished. A magnet is molded into or otherwise affixed to an extension of the first portion and the second portion of the rotatable member is shaped to receive a shaft. Relative rotation is permitted between the first and second portions of the rotatable member so that the shaft will not be seized in position if the rotatable member is jammed within a stationary portion of the is sensor.
In control systems for marine vessels, it is important for a controller to be able to know the actual current position of the outboard drive as it pivots about a steering axis in response to steering commands from the operator of the marine vessel. The angular position of the outboard drive about its steering axis can be measured by various types of sensors that are well known to those skilled in the art. However, linking the sensor to the actual steering mechanism can be difficult because of the lack of space close to the location of the steering axis and, furthermore, because of the fact that the outboard drive rotates about a different center of rotation than the steering actuator. In other words, a steering actuator can move in an arcuate path of a significantly greater radius than the location at which the steering actuator can be readily attached to a sensor. Although various linkages can be employed to connect the steering actuator to the sensor, in order to determine the actual position of the steering actuator, these methods can require complex and expensive linkage arrangements. It would therefore be significantly beneficial if a relatively inexpensive method could be provided for causing a sensor to move in coordination with a steering actuator so that the position of the steering actuator can be monitored, even though the steering actuator moves along an arcuate path that differs in radius of curvature than the guide arm attached to the sensor for conveying the steering actuator position to the sensor so that the steering actuator position can be sensed by a control system.